A triumphant Donald Trump returned Wednesday to Indiana where he hopes to deal a potentially fatal blow to Ted Cruz in the state’s critical standalone primary next week.

Bolstered by bigger-than-expected wins in five Northeastern primaries Tuesday night, he sought to cement his front-runner status and establish himself as the Republican Party’s inevitable nominee with a pair of nationally televised events in Indianapolis.

"If we win Indiana, it’s over!” Trump declared during a rally at the Indiana State Fairgrounds that drew about 5,000 people.

He was joined on the campaign trail by his son, Donald Trump Jr., and Indiana University coaching legend Bobby Knight, who told the audience at a Fox News Town Hall event at Hilbert Circle Theatre that he and Trump had something in common.

“If we’re involved with something where we want to win, and particularly something that’s necessary, if there is something out there where we need to win, we’re going to try to beat your ass every time,” Knight said to a cheering crowd of Trump supporters, many of whom had waited nearly two hours in a line that winded around several blocks near Monument Circle before getting into the event.

The Texas senator is hoping Fiorina, a former Hewlett-Packard Co. CEO, will give him an additional edge with Hoosier voters.

He is facing a must-win situation in Indiana. The state’s 57 delegates represent his best hope for preventing Trump from getting the 1,237 delegates he needs to win the nomination outright and avoid a contested national convention this summer in Cleveland.

“Where we are right now, nobody is getting to 1,237 delegates,” Cruz said during the rally. “I’m not getting to 1,237 delegates, and Donald J. Trump is not getting to 1,237 delegates. And the Hoosier state is going to have a powerful voice in making that clear.”

The Fiorina announcement was Cruz’s second major surprise announcement since turning his focus to Indiana last week.

He and the race’s third candidate, Ohio Gov. John Kasich, announced an unprecedented noncompete agreement on Sunday that essentially turned Indiana into a two-man race. Under the deal, Cruz agreed not to campaign in two Western states, while Kasich agreed to abandon Indiana. The two men are hoping the arrangement will help stop Trump by consolidating opposition to the front-runner behind a single candidate.

Trump, who has called the alliance “collusion,” dismissed the Fiorina announcement on Wednesday as the latest sign of Cruz’s desperation.

"Cruz can't win," he said at his rally. "What's he doing picking a vice president?"

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Someone in the Pam Am offices expressed their opinion about Senator Ted Cruz. Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

Senator Ted Cruz announced during a rally at the Pavilion at Pan Am Plaza, that if he is the Republican presidential candidate, his running mate for vice-president would be Carly Fiorina, a former candidate herself.
Matt Kryger/IndyStar

He told town hall host Greta Van Susteren earlier in the day that Cruz’s announcement “gets him in the news cycle because he’s been totally taken out. He had a horrible day yesterday. … He came in and he got nothing and I think he wanted to do something to get out of that negative cycle. And in that sense it was probably good for him. But people will not like it.”

Trump’s growing momentum is a major concern for Cruz and other Republicans who fear Trump can’t win against the Democratic nominee in November. Even before Trump's five-primary sweep on Tuesday, polls showed him leading Cruz by 6 to 8 points in Indiana. The wins could persuade voters to coalesce behind Trump.

Sam Rosebrock, 41, of Greenwood, began the week supporting Cruz during the Texas senator’s stop at Jockamo Upper Crust Pizza in Greenwood. By Wednesday, he had switched his allegiance and could be found cheering on Trump at the fairgrounds.

“I think he’s pretty much got it wrapped up after last night,” he said. “He’s going to win it. My opinion is everyone just needs to get behind him and beat Hillary.”

Cruz is facing a difficult task because to beat Trump, he needs to attract two disparate group of voters.

First, he needs to win over the state’s large evangelical Christian population, a group that has helped him win in other states such as Iowa and Wisconsin. A Fox News poll released last week showed those voters were split almost evenly between Trump and Cruz in Indiana.

In an effort to appeal to religious conservatives, Cruz has slammed Trump for saying that transgender people should be allowed to use the bathroom of their choice.

But in doing so, he risks alienating another key constituency: Kasich supporters. They tend to be more concerned with fiscal issues and see divisive social issues as a distraction.

Before attending a Cruz rally last week, Zach Shupe, a 20-year-old college student at Indiana University-Purdue University Indianapolis, thought he would vote for Cruz.

But after seeing him speak and then attending Trump’s town hall event, he said he now planned to back Trump.

“Originally, before I saw Ted Cruz and some of his ideas on social issues, I was really for Ted Cruz. But I think he’s in many ways the face of a dying GOP on social issues, and I think that those are ways the GOP can really shoot themselves in the foot,” he said.

Trump rally attendees head toward the Republican front-runner's podium area, about two hours before his scheduled speech, Indiana State Fairgrounds, Indianapolis, Wednesday, April 27, 2016. Robert Scheer/IndyStar